1. Field of the Invention
The present invention relates to integrating flight deck modules, and more particularly, to integrating and simplifying Solid State Flight Deck Modules in transport systems, for example, aircrafts.
2. Background
Flight Deck Modules:
The flight deck area of an airplane (cockpit) includes a large number of devices for flight crew control and monitoring of different aircraft subsystem functions such as climate control, air conditioning, electrical power systems, window heat, passenger signs, anti-ice systems, hydraulics, cargo heat, bleed air, and fuel systems and other systems. These devices (various types of switches, small displays, backlit annunciators, relays, gauges, etc.) are arranged in modules which can be removed and replaced on the flight line (may also be referenced as “Line Replaceable Units” or “LRUs”).
Flight deck modules (or “units”, the term module and units is used interchangeably throughout this specification) are grouped together and attached to a structure often referred to as panels, which are located in view and reach of the flight crew. The modules are connected through wiring to relays, valves, motors, and electronic LRUs.
The flight deck modules receive aircraft AC and DC power for switching and powering various components. The DC power is typically 28 VDC, but the voltage is not regulated and can vary over a wide range, for example, from 16 VDC to 32 VDC.
Panel Lighting:
The flight deck modules typically contain lightplates on their front face, which provide backlit nomenclature (indicia or system) describing the function of the devices. The lightplates are typically made of clear polycarbonate, which are painted first with white paint, then with a dark paint. The dark paint is etched away to form the nomenclature. Light shines from the back of the lightplate through the polycarbonate and the white paint where the nomenclature is etched. Lightplates receive modulated 5 VAC power for the backlighting from Dimming Control Units (DCUs) (108, FIG. 1). Potentiometers or rheostats located on a flight deck module in each panel area provide a continuously variable signal to the DCUs (108). DCU 108 convert 115 VAC power to 5 VAC, and then truncate each half sine waves in proportion to a signal from the potentiometer or rheostat, thereby modulating the root mean square (RMS) voltage level of 5 VAC power to effect different levels of lightplate lighting brightness. A commercial airplane typically uses about 20 DCUs. Small displays and gauges also have adjustable backlighting which use DCU 108 power.
The brightness of all panels can optionally be raised or lowered together by sending a signal to all DCUs that is summed with the individual panel brightness control signal. This signal originates from a Master Brightness Control (MBC) module (109, FIG. 1). The MBC module processes a signal from ambient light sensors and mixes it with a master brightness rheostat or potentiometer.
Annunciators:
Flight deck modules also use annunciators, which have bright backlit nomenclature to alert the pilot of abnormal conditions. The nomenclature is typically not visible when the annunciators are not backlit. The alerts (backlit nomenclature) are in different colors indicating the severity of the abnormality and how quickly the pilot should take corrective action.
Typically, the annunciators have two levels of brightness, dim for night time ambient conditions and bright for sunlight ambient light and testing. Annunciators receive power from a Master Dim and Test (MD&T) system (107, FIG. 1), which sends unregulated 28 VDC power for the Bright and Test modes, and 12 VDC regulated power (sometimes dim voltage power is produced by a diode placed on a 28 VDC source to reduce the voltage) for the Dim Mode. The flight crew selects the mode by using a three-position switch, which sends signals to the MD&T system. The test position commands bright mode power to all the annunciators and closes ground paths from all the annunciators at the same time. When not in Test Mode, the ground paths for individual annunciators are closed by electronic LRUs or circuitry, which detects the abnormal conditions.
Any one annunciator receives power from a single MD&T assembly (107, FIG. 1). Different annunciators on a single module may receive power from different MD&T modules.
Typically, all MD&T modules receive power from main DC buses (2 to 4 different busses), but some aircrafts power MD&T modules with a battery backed up bus. Typically, an aircraft has at least one MD&T assembly for each different DC bus, and often as many as 20, depending on the number of annunciators and the capacity of the individual MD&T Dim power control circuit (power supply for regulated dim power).
Communications Network:
In conventional aircrafts, plural (sometimes thousands) discrete wires connect the flight deck with subsystems in other parts of the airplane. New aircraft designs have tried to reduce fabrication and installation costs, weight and volume by employing data busses.
FIG. 1 shows an example of a conventional system 100 that attempts to integrate the flight deck modules with other subsystems. The flight deck (with modules 101) is connected to other electronics through redundant system data busses, which link multiple destinations to the flight deck. Data bus controllers (for example “Overhead Panel Bus Controller 105” in FIG. 1) receive and transmit digital data from local data busses connected to the data concentrators 104. The data concentrators 104 (“Panel data concentrator(s) 102” and “Overhead Panel card files 103” in FIG. 1) convert analog and discrete data into digital data; and digital data to analog and discrete data. Analog and discrete signals are generated by plural components within the flight deck modules (101).
Turning to FIG. 1 in more detail, flight deck modules 101 are coupled to a separate overhead panel ARINC 629 system (OPAS) 112. OPAS 112 includes plural overhead panel interface card (OPIC) 104 and plural overhead panel bus controllers (OPBC) 105. OPIC 104 include plural panel data concentration units 102 and overhead panel cardfiles 103 that interface between flight deck modules and OPBC 105. Output from OPAS 112 is sent to LRUs 106.
As discussed above and shown in FIG. 1, the flight deck modules 101 use several MD&T modules 107 and DCUs 108. DCUs 108 use a variable 0 to 5 VAC signal to control panel lightplate brightness. The MD&T units 107 output a 28 Vdc unregulated, or a regulated 12 Volt signal to control annunciator brightness level. MBC module 109 is also coupled to DCUs 108 and can control the brightness of all panels. The voltage sources (28 VAC) and (115 VAC) are shown as 110 and 111.
Conventional integration of flight deck modules has shortcomings. For example, the numbers of wires and components involved in integrating flight deck modules result in a complicated and difficult to maintain design. The use of plural DCUs and MD&Ts also result in a complex design. Furthermore, the way power is distributed among the various modules can result in electromagnetic interference that can be harmful to other electronics being used in the aircraft. The present approach (with numerous wires, power sources, and plural components) can also result in high heat dissipation that can result in overheating and cause damage to the panels/aircraft.
Therefore, there is a need for a system to integrate flight deck modules in a simplistic design reducing the need for discrete wiring and plural components.